FabDigit

EPM vs EPDM and 2 more: properties

EPMEPDMSiliconeTPE

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0.01 GPa8.7×10⁻⁴ Msi
0.01 GPa8.7×10⁻⁴ Msi
0 GPa3.19×10⁻⁴ Msi
0.01 GPa0 Msi

Shear Modulus

0 GPa2.9×10⁻⁴ Msi
0 GPa2.9×10⁻⁴ Msi
7.5×10⁻⁴ GPa1.09×10⁻⁴ Msi
0 GPa4.35×10⁻⁴ Msi

Bulk Modulus

2 GPa0.29 Msi
2 GPa0.29 Msi
2 GPa0.22 Msi
2 GPa0.29 Msi

Poisson's Ratio

0.49
0.5
0.49
0.48

Tensile Strength (Ultimate)

14 MPa2 ksi
12 MPa1.7 ksi
8 MPa1.2 ksi
8 MPa1.1 ksi

Elongation at Break

320%
400%
500%
480%

Hardness, Shore A

70 Shore A
70 Shore A
50 Shore A
65 Shore A

Tear Strength

30 kN/m171 lbf/in
25 kN/m143 lbf/in
25 kN/m143 lbf/in
25 kN/m143 lbf/in

Compression Set (22 h, 70 °C)

18%
20%
20%
30%

Hardness, Shore D

22 Shore D
20 Shore D

Compressive Strength

3 MPa0.44 ksi

Flexural Modulus

0.02 GPa0 Msi

Shear Strength

5 MPa0.73 ksi

Physical

Density and transition temperatures.

Density

1.12 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³
0.96 g/cm³0.03 lb/in³

Glass Transition (Tg)

-55°C-67 °F
-55°C-67 °F
-125°C-193 °F
-55°C-67 °F

Water Absorption (24 h)

0.8%
0.5%
0.3%
0.3%

Refractive Index

1.41

Light Transmission

88%

Melting Temperature (Tm)

165°C329 °F

Water Absorption (Saturation)

0.8%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.25 W/m·K0.14 BTU/hr·ft·°F
0.3 W/m·K0.17 BTU/hr·ft·°F
0.22 W/m·K0.13 BTU/hr·ft·°F
0.2 W/m·K0.12 BTU/hr·ft·°F

Specific Heat Capacity

2,000 J/kg·K0.48 BTU/lb·°F
2,000 J/kg·K0.48 BTU/lb·°F
1,300 J/kg·K0.31 BTU/lb·°F
1,900 J/kg·K0.45 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

180 µm/m·K100 µin/in·°F
180 µm/m·K100 µin/in·°F
270 µm/m·K150 µin/in·°F
200 µm/m·K111 µin/in·°F

Max Service Temperature (continuous)

150°C302 °F
120°C248 °F
200°C392 °F
105°C221 °F

Min Service Temperature

-50°C-58 °F
-50°C-58 °F
-60°C-76 °F
-50°C-58 °F

Limiting Oxygen Index

19%
19%
26%
19%

Max Service Temperature (short-term)

175°C347 °F
160°C320 °F
250°C482 °F
135°C275 °F

Heat Deflection Temp. @ 0.45 MPa

55°C131 °F

Vicat Softening Point (B50)

60°C140 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Dielectric Strength

25 kV/mm635 V/mil
25 kV/mm635 V/mil
22 kV/mm559 V/mil
20 kV/mm508 V/mil

Dielectric Constant (1 MHz)

2.8
3
3
2.6

Dissipation Factor (1 MHz)

0.004
0.007
0.002
0.0015

Volume Resistivity

1×10¹⁵ Ω·cm
1×10¹⁴ Ω·cm
1×10¹⁵ Ω·cm
1×10¹⁵ Ω·cm

Comparative Tracking Index (CTI)

600 V
600 V

Surface Resistivity

1×10¹⁴ Ω

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

95 / 100
85 / 100
90 / 100
88 / 100

UV / Weathering Resistance

97 / 100
95 / 100
97 / 100
70 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

30 / 100
30 / 100
20 / 100
25 / 100

Formability (cold)

85 / 100
90 / 100
95 / 100
90 / 100

Mold Shrinkage

2.5%
2.5%
2.5%
1.8%

Mold Temperature (typ.)

175°C347 °F
175°C347 °F
180°C356 °F
40°C104 °F

Weldability

15 / 100
20 / 100
65 / 100

Polishability

20 / 100
85 / 100
20 / 100

Processing Melt Temperature (typ.)

100°C212 °F
25°C77 °F
210°C410 °F

Melt Flow Rate

20 g/10 min

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

95 MJ/kg40,843 BTU/lb
95 MJ/kg40,843 BTU/lb
110 MJ/kg47,292 BTU/lb
95 MJ/kg40,843 BTU/lb

Embodied Carbon (primary production)

3.4 kg CO₂/kg
4 kg CO₂/kg
6.5 kg CO₂/kg
3.6 kg CO₂/kg

Embodied Water

110 L/kg13.2 gal/lb
150 L/kg18 gal/lb
250 L/kg30 gal/lb
130 L/kg15.6 gal/lb

Typical Recycled Content

2%
5%
0%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

12 kN·m/kg
10 kN·m/kg
7 kN·m/kg
8 kN·m/kg

Thermal Shock Resistance Index

3
3
3
1

Same in both: Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s

Strength versus weight

Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scaleEPDMSiliconeTPE

Manufacturing and finishing

CapabilityEPMEPDMSiliconeTPE
Injection moldingYesYesYes
Default conditionSolidMedical GradeShore A 30 to Shore A 90
Relative cost$$ Standard$$ Standard$$$ Premium$$ Standard
Min. machined wall
Best machined surface
Chrome Plating (Plastic)YesYesYes
EMI Shielding CoatingYesYesYes
Soft Touch CoatingYesYesYes
Spray PaintingYesYesYes
UV CoatingYesYesYes

Ready to make it?

Upload a CAD file and FabDigit prices the part in EPM and EPDM side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.